Someone to Watch Over by Trish MacDonald Skillman

In her disheveled little house on a run-down midwestern street she has seen the signs he left her: a repaired step, a clean set of dishes, even a new nightgown on her bed. Someone is watching over her and her two children. . . .

Devastated by the death of her husband, slowly Kate Eldridge begins to live again. Now she has a second chance--at love and at happiness. But Kate doesn't know her guardian angel has plans of his own, or what violent secrets haunt him, or how far he will go to keep her and her children in her sight and in his hands. . . .

It began as an act of kindness. Now it has turned into a dangerous obsession. The man who is watching over her has crossed the line into madness. . .and into terror. . . ." -- from the back cover

My thoughts:

This was an intense thriller featuring a man who slowly becomes a madman who creates his own reality.